Scanning members such as scanning lasers are used in a variety of products for a variety of reasons. For example, laser printers use a scanning laser to create an image by scanning a modulated laser beam across an area covered with a material that is influenced by the laser to create an image that is then transferred to a piece of paper. In order to create a detailed, high resolution, image, the position and scan direction of the laser beam must be precisely known and controlled. Typically this control is achieved by using components manufactured to precise standards to construct the scanning laser and calibrating the scanning laser once it has been assembled. Unfortunately, the operating characteristics of the components used to construct the scanning laser tend to change over time. Thus, the precision of the scanning laser tends to change with conditions and time. For example, the performance of many electrical and mechanical components varies with temperature. Thus, the operation of a scanning laser may vary as the unit heats up during use. Therefore, what is needed is an inexpensive and reliable method and apparatus for determining the position and scan direction of a scanning member over a long period of time in a variety of environmental conditions.